Arc-preventing device



IN VENTORS ATTORNEY J. CLOSSMANN 'ET AL ARC PREVENTING DEVICE Filed Dec.16. 1922 I, Jidz'm- LYonmannlciarzdzlalcrxtadi Patented Oct. 16, 1923.

UNITED STATES JULIUS CLOSSMANN ANiD HEINRICH HALBEBSTADT, OF VIENNA,AUSTRIA.

ARC-PREVENTING DEVICE.

Application filed December 16, .1922. Serial No. 807,441.

To all whom it may concern:

Be it known that we, JULIUS CLOSSMANN,

engineer, and HEINRICH Hannnns'ranr, en--.

ginee-I', both citizens of the Republic of Aus 6 tria, residingsit-Vienna, in the Republic of Austria, have invented certain new anduseful Improvements in Arc-Preventing Devices. of which the following isa specification.

It is known that in electric switches, more especially those for heavycurrents, the arcing or sparking when the circuit is broken rapidlyrenders the contacts useless. Consequently many devices forextinguishing arcs or sparks have been suggested, which. however, byreason of the expensive and complicated auxiliary apparatus required areonly employed in cases where very ex ceptional dangers or disadvantagesresult from the arcing or sparking.

The subject of the invention is a switch device wherein by the shape ofthe contacts and also their arrangement and movement, the occurrence ofarcing at the original con tact places i rendered quite impossible, andany arcs that may be formed at other places are efliciently suppressed.This result is obtained according to the invention without any auxiliaryapparatus bg' suitably haping the contacts and by t e connection of onecontact with the other; additional advantages result from the relationof the arm to the movable contact nd by its movement.

Hereinafter we particularize in the'de' scription of embodiments of ourinvention, show embodiments in the accompanying drawings, and finallypoint out the invention in the appended claims.

The invention is diagrammatically illustrated in the accompanyingdrawings, in which:

Fig. 1' is'an elevation of the contacts of the present invention, thedotted line position of the movable contact being the normal circuitingposition, and thefull line position of such movable contact being thefinal contact position'as the movable contact moves to open circuitingrelation;

Fig. 2 is side view of the same, the movable contact being shown inclosed circuiting position in full lines, and addit onally shown inposition as it opens, and In full open circuit position in dotted lines;Fig. 3 is asimilar side v1e w, showin circuit closed position in fulllines and circuit obviously it may open position in dotted lines, with adifierent form of movable contact;

Fig. 4 is a side view showing aslightly modified form of contacts; I

-Fig. 5 is an elevation of Fig. 4, showing additionally the position ofthe movable contact in its final contact position;

Fig. 6 is an elevation artly in section of a further embodiment o theinvention, the form of the contacts being modified;

Fig. 7 is a diagrammatic view illustrating the arc formation and showingin dotted lines the magnetic field about the arm of the movable contact;

Fig. 8 is a side view of a structure embodying the invention of theforegoing,' views;

Fig. 9 is a plan view of the same; and

Fig. 10 is a view taken from line 10-10 of Fig. 8.

Similar characters of reference indicate corresponding parts throughoutthe several news.

VVithmore particular reference to Figs. 1 and 2, the'movable contact ais here shown in the form of a figure of revolution, though be of anyother form, the width of which alters in the plane of the contactsurface or perpendicularly to such surface. The fixed contact hereindicated at b, is longitudinally'divided with the arms thus formedslightly flattened in the direction of motion, as indicated at c, Fig.2, with the proximate edges of said arms'divergent, as indicated at d,Fig. 1. The movable contact a, is carried by an arm m, o cratingrelative to remote center, thoug other methods of support and o rationof the movable contact can be readily utilized. In the normal circuitingrelation between the movable contact a and the fixed contact arms I), asindicated by dotted lines in Fig. 1. and full lines in Fig. 2, it willbe noted that the contact area between these contacts is a comparativelysmall area where the substantially rounded or conical operative surfaceof the movable contact co-operates with the immediately underlyingportions'of the contactarms b. As the movable contact a moves to opencircuiting position, it will be apparent that the line of contactbetween the respective contact members is directed angularly' of thearms 1;, due to the divergent edges d and laterally or tact a, due tothe surface 0 ch contact and radially of the conto the divergence of theedges of the arms 2. Thus without interrupting the electrical engagementbetween the contacts, it will be apparent that the normal contact area,when the contacts are in circuit-ing position, is entirely distinct andwidely separated from the contact area of such contacts at the momentthe electrical engagement between the contacts is broken. If arcingresults in the separation of the contacts, it will be appar- The movablecontact can also be formed for example by a roller a, (Figures 4; and5), or of a spherical surface or of a cone, or in the form of a disc ofrhomboidal form or any other body having avarying breadth. The securingof the movable contact in the contact position can take place forexample by spring pressure which can be eiiected quite easily when thefixed contact has an inclined or ramped surface 0 (as shown in Fig. 2).This ramped surface, when the current is flowing, bearing against thecontact (1, us to the. spring produces a sulficient amount of frictionor pressure to hold the movable contact firmly in closed position.

A recess 7t shown in Figs. 2, t and 5 of corresponding form to themovable contact serves as a rest surface for the movable contactto.increase the security against unintentional movement of the lever.

Instead of the securing devices just described, there can be used thespring clip or tongue is, shown in Fig. 6, from which the movablecontact arm m can only be removed when the extensions 2' are pressedtogether.

In cases where, as in Figs. 1, 2, and 3, the movable contact arm mpasses" between the fixed contacts b, in order to prevent arcing orsparking between the parts at these places, the fixed contacts can beprovided between the arm m and the side surface of the fixed contactsI), F), with plates of insulating material, as indicated at 1 in Fig. 1.

In Figs. 8, 9, and 10, a structure is shown which embodies the inventionherein described. A slate base n has a conductor 0 with thumbscrew 0thereon, which conductor connects electrically with one end of one ormore convolutions g and the member m, which has the contact a. Anotherconductor r with thumbscrew 1" electrically connects with contact F2.

The convolution or convolutions surround a core a, and the arm m islimited in its movement by the shoulder t.

circuit The extinction of the arcs or sparks atthe edge of the movablecontact or roller, etc., occurring during the drawing away of themovable contact from the other contact is effected by suitably formingthe movable contact arm m substantially perpendicular to the directionof motion of the movable contact, and subjecting the arm to the actionof a powerful spring or other means capable of imparting to it a rapidmovement. This tondition is also approximately fulfilled by a circularmovement of the current arm, as shown in Figs. 2 and 7; The extinctionof the arcs or sparks in this case takes place by the blowing out of anyarc that may form. and furthermore a back elec tromotive force isproduced, which prevents the occurrence of an arc.

Fig. 7 shows diagrammatically the most favorable conditions in thisrespect. Around the movable conductor m as well as around the are e as asecond conductor, there are lines of force which repel each other andthus extinguish the arc. Above all, the lines of force f which areproduced around the movable conductor m and which in the movement of theconductor m. out those of the are produced, generate a backelectromotive force in a direction contrary to the arrows g and p whichincreases with the rate at which the lever arm moves. This elcctromotiveforce acts in the opposite direction to the current indicated by g and pflowing in the arcs or sparks, and consequently effects theinstantaneous extinction of the latter.

When the switch is closed with the contact (1., in effective contactualrelation to the contact 7),, and a normal or less than normal currentflows therethrough, the current sets up fields of force, as is wellknown, around the contact a., contact 6., and arm 77?. On the separationof the contact (a, from contact 6., as in Fig. 4, an arc is produced,and this sets up in the known manner its field of force. The movement ofthe arm m. cuts the lines of force surrounding the arc. At the same timethe arc. shifting its position cuts the lines of force of conductor m.These relations, of course, change rapidly, and cannot be shown in thedrawings with definiteness, though they are indicated in Fig. 4, andwill be clear to anyone skilled in the art. Increase of currentincreases the lines of force. \Vhen, then, a current larger than thenormally intended or excess current flows through the parts. on thebreakin of the circuit, then the fields of force wi 1 be correspondinglyincreased. The field around the arm m. will act to blow on the arc, ascertain of the lines of force repel each other, under Amperes law ofparallel and oblique circuits; or the arc will move away from the fieldof force of arm m. as it also always (lesires to place itself into thepath of least resistance. This movement of the arc and attenuationcauses a cutting of lines of force. By the co-operation of the parts, acounter or opposing electromotiveforce is set up. The speed of movementof the arts increases the same. This counter e ectromotive force acts asstated to extinguish the arc. When the are is split into two parts aswhen two contact members b. are used, the extinguishment is quicker.

It will have been seen that the contact a. has an effective contactsurface with contact b., under normal conditions. When the contact a. ismoved along contact- 6., the contactual surface is decreased andgradually changed. But as the parts separate, the last contactualrelationship is at a portion of the contact 1)., distant as far aspossible from its' initial efi'ective'contact surface, and is at aportion of contact a. distant as far as possible from its initialeffective contact surface, namely at its perimeter in Fi 1 and 2. Noarcing takes lace at the initial contactual surfaces, ut at a distancetherefrom. Any arcing produced does not burn or fuse the effectivecontact surfaces.

It is obvious that the, above arrangement is entirely independent of thedirection of the current, and that the efi'ects sou ht are obtainedquite consistently with eit erdi rection of the current.

It is of course a parent that the switch construction descri ed isequally effective whether the movable contact a, is a circuiting memberor whether it is merely a bridge member between the two independentcircuiting members which would under such circumstances be the separatearms 6.

While we have herein shown and described several practical embodimentsof the invention, it is understood that changes may be made thereinwithout departing from the spirit and scope of the invention as claimed.

What we claim is: I

1. An are preventing device, comprising cooperating switch members, eachhaving on the switch member itself a normal contact area forming thesole electrical connection when the members are in circuiting position,and each having a contact area on the switch member itself independentfrom said normal contact area and serving as the sole electricalconnection as the members approach an open circuitin relation.

2. An are preventing, evice, comprising cooperating switch membershaving relative movement in contact from a normal closed "circuitrelation to an open circuiting relation, the electrical contact area be-.tween the switch members themselves in normal closed circuit relationbeing spaced from the contact area between themembers themselves as saidmembers approach an open circuiting relation. 3. An are preventingdevice, comprising cooperating switch members having relative movementin contact from a normal closed gircuiting relation toward an opencircuiting relation, said members themselves being relatively formed toany possible tendency in the separation of the members between points wolly free of contact when the members are in normal closed circuitingrelatiom 4. An are preventing device comprising two contacting members,one movable with respect to the other to open or close the circuit, themembers being so relatively formed as to wholly change the point ofcontact between the members themselves with respect to each other fromtheir posi-. tions in cir'cuiting relation to their positions at theinstant of breaking the circuit.

5. An arc preventing device comprisingtwo contracting members, onemovable with respect to the other to open or close the circuit themembers being so relatively formed as to maintain a definite contactareabetween the members themselvesin circuit closed position and compel awholly independent relative contact area between the members themselvesat the instant of opening the circuit, and means to operate one memberwith respect to the other to insure such contact varlation.

- 6. An are preventing device comprising contact members adapted forrelative movement, one of said members havingl a contact portioninclined with respect to t e path of movement of the contact portion ofthe other member, whereby the contact surfaces of the members themselvesvary in position during the movement of the members relative to eachother.

7. An are preventing device comprising contact members adapted forrelative movement, one of said contact members having spaced inclinedcontact portions and the other of said members having a rounded contactportion, and means operating between the inclinedcontact portions of thefirst member to move the other of said members, whereby to constantlychange the contact area between the members themselves during theirrelative movement. I

8. An arc preventing device comprising relatively movable contactmembers, one of said members clined with respect to the other contactmemher, said othercontact member being formed of a body of revolutionadapted for movement lengthwise the inclinedcontact portion of the othermember, whereby in opening' the circuit the contact areas between themembers themselves are constantly changed.

9. An arc preventing device comprising relatively movable contactmembers, one of having a contact portion insaid members having a contactportion inclined to the path of movement of the other of said members,said other member having a curved contact space to engage the firstmember, whereby in the open circuiting movement of the members theelectrical contact between the members themselvesis directed at an angleto the path of movement of the operated member.

10. An are preventing device comprising contact members. one movablewith respe t to the other, one of sa d contact members havin spacedinclined contact portions and the otlier of said member having a curvedcontact space bridging the space between the inclined contact portionsof the first member, and means for operating said other member to causethe line'of contact to move on divergent lines at an angle to the pathof movement of such other member during the open circuiting movement ofthe members.

11. An are preventing device comprising relatively movable contactmembers, one of said members having spaceddivergent contact portionslaterally inclined with respect to the path of movement of the othermember, such other member having a contact surface bridging the spacebetween the contact portions of the first member, and means to operatesuch other member along and away from the first member, whereby thecontactual surfaces become less until separation takes place.

12. An arc preventing device comprising relatively movable contactmembers, one of said members having longitudinally disposed spacedcontact surfaces having terminal relatively divergent portions, theother of said contact members having a curved face bridging the spacedcontact sur faces of the first member to maintain c-on tact whileproviding portions of each contact member normally out of electricalengagement, and means for operating such curved contact member toutilize normally free contact portions ct both members as the finalcontact area.

13. An are preventing device comprising relatively movable contactmembers, having their surfaces relatively formed to constantly changethe contact area between the members themselves as said members move toopen the circuit, and a rod connected to and operating one of saidcontact members, said rod being arranged at right angles to itsconnected member.

14. An are preventing device for preventing or extinguishing arcs orsparks at the contacts of electric switches, characterized in that oneorlooth of the contacts has or have an extension of breadth, acontraction, a flattening or a curvature, which varies in amount andwhich during the sliding of the contacts oneach other produced by themovement of the switch, effects a. continual change in the places ofengagement of the contacts themselves so that the separation of thecontacts themselves finally takes place at places which lie at adistance from the original two places of contact.

15. An are preventing device, comprising a contact, a second contact,said contacts being movable one in respect to the other, said contactshaving means decreasingly varying the contactual surfaces of the saidcontacts, from full effective contact up to no contact on the point ofseparation of the contacts under maintenance of electrical engagementbetween the contacts, and an arm.

for said movablecontact arranged perpendicular to the direction ofmotion for each position of the movable contact, and capable of a veryrapid motion from closed circuit position to open circuit position.

16. An are preventing device, comprising a contact, a second contact,one movable in respect to the other, said contacts having meansdecreasingly varying the contactual surfaces of the said contacts, fromfull effective contact up to no contact on the point of separation ofthe contacts under maintenance of electrical engagement between thecontacts, an arm for said movable contact arranged perpendicular to thedirection of motion for each position of the movable contact and capableof rapid motion from closed circuit position to open circuit position,and means holding the contacts in closed circuit position.

17. An are preventing device, comprising a movable contact, a secondcontact having an inclined cut away portion oblique to the path ofmovement of the movable contact for decreasing the contactual surfacesas the movable contact moves over the second contact until separationtakes place, and means elastically pressing said conta'ts together onnormal current flow, and separating the contacts and giving the movablecontact a rapid motion away from the second contact.

18. An are preventing device, comprising a contact, substantiallycircularly movable in respect to a pivotal point, a second contacthaving an effective contact surface, and a curved portion curved in linewith the path of motion of the movable contact, and having an inclinedportion oblique to the direction of motion of the movable contact,whereby the varyin contactual surfaces change in two directions at rightangles to each other on the movement of the movable contact over thesecond contact, and means on the movable contact pressing said contactstogether on normal current flow, and separating the contacts and givingthe movable contact a-rapid motion away from the second contact.

19. An are preventing device, com rising a circular contact, a secondcontact aving an effective contact surface, and a portion curved awayfrom the effective contact surcontacts from each other.

20. An are preventing device, comprising a pivoted conductor, movable ina plane, a contact at right angles thereto at its-free end, and movabletherewith, and a second contact having a surface in a planeperpendicular to the plane in which the conductor moves and having aportion curved to substantially conform to the path of movement of thefirst contact, the edge of the curved portion being closer to the edgeof the first contact than any other portions of the contacts, wherebyany arc formed between edges is extinguished in the movement ofdisengagement of the contacts, by the field produced by the currentpassing through the conductor and the counter electromotive forcecreated.

21. An are preventing device, comprising an electrical contact, havingan effective contact surface, a second contact having an efiec tivecontact surface, all electrical contact between the said contacts beingmade by the contacts themselves, the said contacts when contacting inclosed circuit position having their effective contacting surfaces in acommon plane, and a member for one of said contacts movable in a planeperpendicular to the common plane of the contacts, said contactsupporting membernot contacting with the other contact.

In testimony whereof we have hereunto set our hands.

JULIUS CLOSSMANN. HEINRICH HALBERSTADT.

Witnesses:

CARL LONDENBERG, LUDWIG BURIDO.

